There's a word I grew up hearing in rural Mississippi that exists in no dictionary.

Ch'yarn. What the dog had been wallowing in out in the yard — something dead and rotten and unseen in the tall grass.

Nobody who used it could spell it. It was passed entirely by mouth, generation to generation.

Years later I met someone from Baxley, Georgia — 480 miles away — who knew the exact same word, in the exact same sense.

https://imitationofmink.com/chyarn-deep-south-dialect-word/